from .record import Record
from .typeexpr import (
    AtomicType,
    TypeApplication,
    TypeConstructor,
    TypeExpr,
    TypeVariable,
)


class TypeRouter[T]:
    def when_atomic(self, typ: AtomicType) -> T:
        raise NotImplementedError(typ)

    def when_application(self, typ: TypeApplication) -> T:
        raise NotImplementedError(typ)

    def when_constructor(self, typ: TypeConstructor) -> T:
        raise NotImplementedError(typ)

    def when_record(self, typ: Record) -> T:
        raise NotImplementedError(typ)

    def when_variable(self, typ: TypeVariable) -> T:
        raise NotImplementedError(typ)

    def __call__(self, typ: TypeExpr) -> T:
        if isinstance(typ, AtomicType):
            if isinstance(typ, Record):
                return self.when_record(typ)

            return self.when_atomic(typ)

        if isinstance(typ, TypeApplication):
            return self.when_application(typ)

        if isinstance(typ, TypeConstructor):
            return self.when_constructor(typ)

        if isinstance(typ, TypeVariable):
            return self.when_variable(typ)

        raise NotImplementedError(typ)